MAFG-driven osteosarcoma cell progression is inhibited by a novel miRNA miR-4660

Abstract

Osteosarcoma (OS) is the most common primary bone malignancy in the adolescent population. MAFG (v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog G) forms a heterodimer with Nrf2 (NF-E2-related factor 2), binding to antioxidant response element (ARE), which is required for Nrf2 signaling activation. We found that MAFG mRNA and protein expression is significantly elevated in human OS tissues as well as in established and primary human OS cells. In human OS cells, MAGF silencing or knockout (KO) largely inhibited OS cell growth, proliferation, and migration, simultaneously inducing oxidative injury and apoptosis activation. Conversely, ectopic overexpression of MAFG augmented OS cell progression in vitro . MicroRNA-4660 (miR-4660) directly binds the 3′ untranslated region (UTR) of MAFG mRNA in the cytoplasm of OS cells. MAFG 3′ UTR luciferase activity and expression as well as OS cell growth were largely inhibited with forced miR-4660 overexpression but augmented with miR-4660 inhibition. In vivo , MAGF short hairpin RNA (shRNA) or forced overexpression of miR-4660 inhibited subcutaneous OS xenograft growth in severe combined immunodeficient mice. Furthermore, MAFG silencing or miR-4660 overexpression inhibited OS xenograft in situ growth in proximal tibia of the nude mice. In summary, MAFG overexpression-driven OS cell progression is inhibited by miR-4660. The miR-4660-MAFG axis could be novel therapeutic target for human OS.

Identification of mitochondrial RNA polymerase as a potential therapeutic target of osteosarcoma

“…To confirm the bioinformatics observation, we examined POLRMT expression in local human OS tissues. OS tumor tissues (“T”) and surrounding normal bone tissues (“N”) were derived from a total of eleven ( n = 11) primary OS patients [ 19 ]. qRT-PCR assay results, Fig.…”

“…1F ) and protein (Fig. 1G ) levels in established OS cell lines (U2OS and MG63) and primary human OS cells (pOS-1 and pOS-2, derived from two different patients [ 19 ]) were significantly higher than those in the primary human osteoblasts (“Ob”) (Fig. 1F, G ).…”

“…OS tumor tissues and matched surrounding normal bone tissues were from a total of eleven (11) primary OS patients (provided by Dr. Cao’s group at Soochow University [ 19 , 36 ]) with written-informed consents. All patients were administrated at authors institutions, received no prior therapies before surgeries.…”

“…U2OS and MG-63 established human OS cell lines were from Dr. Zhang at Medical College of Southeast University [ 37 – 39 ]. The primary human OS cells, derived from two written-informed consent OS patients, were from Dr. Cao at Soochow University [ 19 , 36 ]. The primary human osteoblasts were from Dr. Ji at Nanjing Medical University [ 40 , 41 ].…”

Proteome-scale profiling reveals MAFF and MAFG as two novel key transcription factors involved in palmitic acid-induced umbilical vein endothelial cell apoptosis

“…The functions of v-maf musculoaponeurotic fibrosarcoma oncogene family protein G (MAFG) and v-maf musculoaponeurotic fibrosarcoma oncogene family protein F (MAFF) are now known as proliferation and differentiation coactivators acting in cooperation with NFE2L2 in the mouse hepatoma cell line Hepa1c1c7 (Hepa1) via the Keap1-NFE2L2 pathway [30], and the protein MAFG acts in cooperation with NFE2L2 (Nrf2) to transcriptionally govern either repressive or activating gene functions in antioxidant response element (ARE)-dependent antioxidant pathways in skeletal muscle cells [31]. The protein MAFG is also involved in bile acid homeostasis [32], liver cancer [33], osteosarcoma [34], and central nervous system inflammation [35]. Von Scheidt M et al [36] demonstrated that MAFF is a novel central regulator of an atherosclerosis-relevant liver network and that MAFF can trigger context-specific expression of LDLR and other genes known to affect coronary artery disease risk.…”